The present invention relates to new 5-acyl, 23-acyl and 5,23-diacyl derivatives of the compounds collectively defined as LL-F28249. These LL-F28249 antibiotics preferably are produced by the fermentation of the microorganism Streptomyces cyaneogriseus subspecies noncyanogenus, deposited in the NRRL under deposit accession no. 15773. The morphological characteristics, compounds and method for their production is disclosed in European Patent Application Publication No. 170,006, incorporated herein by reference.
The LL-F28249 components are complex macrolides which have hydroxy substituents at the 5, 7 and 23 positions. The selective acylation of the 5- or 23-hydroxy group, or both, affords the 5-acyl, 23-acyl and 5,23-diacyl derivatives of the present invention. The present derivatives of the LL-F28249 compounds are useful for the prevention, treatment or control of helmintic, ectoparasiti insect, acarid and nematode infections and infestations in warm-blooded animals and agricultural crops.